Body Fluids Tests

Test Overview

Blood and urine are often tested to find the cause of health problems. But other body fluids also can be tested. Most of these fluids help organs and joints—and the membranes around them—move smoothly. Sometimes a health problem can cause too much fluid to build up in part of the body. The fluid can be tested to look for the reason for the buildup.

Some of the most common body fluids that are tested are:

• Peritoneal fluid in the space (peritoneum) between membranes that line the belly.
• Pericardial fluid in the sac (pericardium) that surrounds the heart.
• Pleural fluid in the space between the membranes that separate the chest and the lungs.
• Synovial fluid in joints such as knees, shoulders, and hips.
• Fluid from the genital area, such as semen or cervical mucus.